<button class="Btn">
  Jelly Button
</button>
<style>
/* From Uiverse.io by vinodjangid07 - Tags: button, jelly, hover effect */
.Btn {
  position: relative;
  width: 150px;
  height: 55px;
  border-radius: 45px;
  border: none;
  background-color: rgb(151, 95, 255);
  color: white;
  box-shadow: 0px 10px 10px rgb(210, 187, 253) inset,
  0px 5px 10px rgba(5, 5, 5, 0.212),
  0px -10px 10px rgb(124, 54, 255) inset;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
}

.Btn::before {
  width: 70%;
  height: 2px;
  position: absolute;
  background-color: rgba(250, 250, 250, 0.678);
  content: "";
  filter: blur(1px);
  top: 7px;
  border-radius: 50%;
}

.Btn::after {
  width: 70%;
  height: 2px;
  position: absolute;
  background-color: rgba(250, 250, 250, 0.137);
  content: "";
  filter: blur(1px);
  bottom: 7px;
  border-radius: 50%;
}

.Btn:hover {
  animation: jello-horizontal 0.9s both;
}

@keyframes jello-horizontal {
  0% {
    transform: scale3d(1, 1, 1);
  }

  30% {
    transform: scale3d(1.25, 0.75, 1);
  }

  40% {
    transform: scale3d(0.75, 1.25, 1);
  }

  50% {
    transform: scale3d(1.15, 0.85, 1);
  }

  65% {
    transform: scale3d(0.95, 1.05, 1);
  }

  75% {
    transform: scale3d(1.05, 0.95, 1);
  }

  100% {
    transform: scale3d(1, 1, 1);
  }
}

</style>
